The present invention relates to electrical fault protection and, in particular, to a system and method for detecting and locating electrical faults.
Conventional electrical systems distribute electrical power from a power source to one or more of a plurality of loads through a network of switches (contactors, circuit breakers, SSPCs, etc.) wires, terminal blocks, and connectors. Factors such as temperature, moisture, aging and vibration, among others, can result in degradation of one or more components of the electrical system, resulting in electrical faults. In particular, arc faults caused as a result of wire abrasion, loose connectors or screws, or carbon scoring provide a low-impedance path that can result in potentially damaging currents. To prevent damage, newer electrical systems include arc fault detection and protection circuitry. In response to a detected fault, the protection circuitry isolates the line including the fault from the rest of the system, typically by operating a switch (e.g., MOSFET, IGBT) located between the fault and the remainder of the system.
While fault detection and protection circuitry is useful in protecting the electrical system from fault conditions, it does not provide information regarding the location of the fault. This is particularly problematic in aircraft applications in which subsequent inspection of the electrical system may not identify transient faults (i.e., arc faults occurring as a result of in-flight conditions such as vibration). This results in higher maintenance costs as additional time must be spent inspecting an entire feeder line between the opened switch and the connected load, sometimes including several hundred feet of wires and connectors, to locate the fault. In addition, in instances in which the fault cannot be detected, the entire feeder line may have to be replaced, resulting in additional maintenance costs.
As known in the prior art, fault locating devices can be used to detect the location of an electrical fault along a particular line, but these systems are not weight or cost-effective for in flight aircraft applications. In particular, a typical electrical system for an aircraft may include hundreds of individual loads, each of which would require a separate fault locating device. The additional cost and weight of adding individual fault locating devices for each load becomes prohibitive.